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Breeding for stress in potato

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This slide describes major stress like late blight, potato colarado beetle and heat stress in potato and recent breeding advancements in it.

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Breeding for stress in potato

  1. 1. Breeding for stress in potato -J.Delince
  2. 2. Constraints in potato resistance breeding • Narrow genetic base.  European cultivated Solanum tuberosum originated from few specimens introduced in Europe in the 16th century, they show severe inbreeding.  Introgression of new alleles from wild species • Multiple ploidy levels in the tuber-bearing Solanum species:  From diploids (2n=2x=24) to hexaploids (2n=6x=72)  Incompatibility barriers between different ploidy levels • Tetraploidy level of the European cultivated potato.  2n=4x=48 (four pairs of 12 chromosomes)  Four alleles possibly different for one locus  High heterozygosity level leading, by crossing two tetra-allelic parents, to a lot of genotypes in the hybrid progeny  Genotype x environment interaction  With traditional breeding, selecting a desirable genotype is a time-consuming process
  3. 3. Late blight of potato • Caused by Phytopthora infestans • Crop losses due to late blight alone have been estimated as high as US$210.7 million in the USA, with control costs totaling US$77.1 million for fungicides. • P. infestans is famous for causing the Irish famine in 1845. Almost 1 million people was died from starvation, malnutrition and disease and another 1 million was emigrated to avoid the famine in Ireland.
  4. 4. Symptoms • This disease damages leaves, stems and tubers. Affected leaves appear blistered • When drying out, leaves turn brown or black in color. When infections are still active, spots appear on the underside of leaves • Affected stems begin to blacken from their tips, and eventually dry out. • Severe infections cause all foliage to rot, dry out and fall to the ground, stems to dry out and plants to die. • Affected tubers display dry brown-colored spots on their skins and flesh. This disease acts very quickly. If it is not controlled, infected plants will die within two or three days
  5. 5. Life cycle • They belong to the group called oomycetes • The asexual cycle of P. infestans begins with the production of multinucleate sporangia. Sporangia can germinate either directly through the production of a germ tube, or indirectly through the production of zoospores. • Thus they have high rate of dispersion by asexual reproduction and high recombination rate through sexual reproduction(A1 and A2 mating types) • Favourable temperature is 22 - 24°C with high RH is conducive for this disease
  6. 6. Sources of resistance Source of Resistance Chromosome number and R-gene S. avilesi 11 -Rpi-avl1 S. berthaultii 10 Rpi-ber1and Rpi-ber2 S.brachistotrichum 4 Rpi-bst1 S. bulbocastanum 8 (Rpi-blb1 and Rpi-bt1), 6 (Rpi-blb2), and 4 (Rpi-blb3 and Rpi-abpt) S. capsicibaccatum 11 Rpi-cap1 S. demissum 5 (R1), 4 (R2 and Rpi-dmsf1), 11 (R3-R11 except R8), 9 (R8) S. hjertingii 4 Rpi-hjt1.1, Rpi-hjt1.2 and Rpi-hjt1.3 S. dulcamara 9 Rpi-dlc1 S. mochiquense 9 Rpi-mcq1 S. papita 8 Rpi-pta1 and Rpi-pta2 S. phureja Rpi-phu1 S. stoloniferum 8 (Rpi-sto1) and 11 (Rpi-sto2) S. venturii Rpi-vnt1.1,Rpi-vnt1.2 and Rpi-vnt1.3
  7. 7. Screening method • Field and green house screening • % incidence and Area under disease progressive curve
  8. 8. AUDPC • For multi-location and multi –seasonal trials • Kufri, Shillong and Ooty • Kufri Jyothi is used as susceptible variety
  9. 9.  9= no visible infection; 8= 10% infection; 7= 11 to 25%; 6= 26 to 40%; 5= 41 to 60%; 4= 61 to 70%; 3= 71 to 80%; 2= 81 to 90%; 1=> 90%; 0= 100% infection.
  10. 10. Variety Resistance Kufri Himalini Moderately resistant to late blight Kufri Shailaja Moderately resistant to late blight Kufri Girdhari Highly resistant to late blight Kufri Himsona Highly resistant to late blight Kufri Sutlej Moderately resistant to late blight Kufri Anand Highly resistant to late blight Kufri Arun Field resistant to late blight Kufri Pukhraj Moderately resistant to late blight Kufri Lalima Moderately resistant to late blight Kufri Kanchan Field resistant to late blight Kufri Pushkar Field resistant to late blight Kufri Badshah Moderately resistant to late blight Kufri Chipsona- 3 resistant to late blight Kufri Chipsona- 4 resistant to late blight
  11. 11. Insect resistance –Colorado potato beetle • CPB is considered as the most important insect defoliator of potatoes
  12. 12. Wild germplasm sources • S.berthaultii – four lobed trichomes exudate • S.chacoense – feeding deterrence by leptin I and II • S.pinnatisectum • S.tarnii • S.polyadenium • S.neocardinesii –glycoalkaloids in leaf
  13. 13. Screening • Field evaluation tests • Laboratory feeding assays • The adults and first instar larvae are used for screening • 10 First instar larvae for 48 hours • 27 adults can be used for 8 hours
  14. 14. • Colorado potato beetle ('Yukon Gold' (susceptible control), USDA8380- I (leptine glycoalkaloids), and ML235-4 (glandular trichomes) • Combination of genetic engineering and natural resistance mechanism
  15. 15. Bt varieties • New leaf – CPB and PLRV • NewLeaf Y Potato –CPB and PVY • NewLeaf Plus Potato – CPB and PLRV • All are from the parent -Russet Burbank Potato
  16. 16. Abiotic stress
  17. 17. Heat stress Wild relatives Tolerance S.Phureja Heat tolerance S.chacoense Heat tolerance S.commersoni Heat tolerance • Critical stage in heat stress is Tuberization and tuber enlargement and stress at this stage cause Poor tuber growth and yield, splitting, internal brown spot • Can cause yield loss upto 18 to 32 percent
  18. 18. Conclusion • This study demonstrates that ELA combined with immunoblot analysis of sHSP accumulation under HS conditions could be considered as a reliable procedure in screening potato genotypes for heat tolerance and for the identification of heat tolerant potato cultivars. • In addition, HSP18 and HSP21 expression under HS present similar patterns in potato plants grown in vitro compared to exvitro grown plants, opening up the possibility for the use of an in-vitro culture for heat tolerance screening
  19. 19. Kufri Surya- breeding
  20. 20. Abiotic stress resistanceGene Protein expressed Trait conferred BADH betaine aldehyde dehydrogenase Drought tolerance COD choline oxidase Drought tolerance T6P Trehalose-6-phosphate Drought tolerance GG-phosphate phosphatase synthase Glucosylglycerol (GG) Drought tolerance mtlD mannitol-1- phosphate dehydrogenase Salinity tolerance P5CS pyrroline-5-carboxylate synthetase Salinity tolerance HvNHX2 Na+/H+ antiporter Salinity tolerance Δ12-desaturase Unsaturated fatty acid Cold tolerance DHAR1 dehydroascorbate reductase Oxidative stress GalUR d-galacturonic acid reductase Oxidative stress

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